The eyelids are important to ocular health because they protect the eyes from airborne contaminants, such as pollen, dust particles or other foreign bodies. The eyelids contain several glands including the lacrimal glands and the specialized form of the sebaceous glands, the meibomian glands, which produce layers of tear film that are critical for healthy eyes.
The eyelids are subject to problems like blepharitis, dry eyes and inflammation of the meibomian glands. Another complication is the infestation of the arachnid, Demodex folliculorum (Demodex mites). The Demodex mite infestation is common in humans; anecdotal evidence suggests that the mites can be found in ten percent of the eyelashes of healthy persons. The occurrence of the infestation may also be age related.
Demodex mites reside inside the sebaceous glands and hair follicles. They cause damage to the cell walls by sucking nutrients from the hair roots. They burrow into the skin, lay eggs, introduce bacteria, and infect the skin. Some of the symptoms of infestation include itching and inflammation of the eyelids. Additionally, there is evidence that the mites can also be one of the causes of the skin disease rosacea.